1. Field of the Invention
The present invention relates to a heat pipe, and particularly to a micro grooved heat pipe.
2. Related Art
In industry, there are various parts and components that generate heat during operation. For example, in the electronics and computer industries, it is well known that computer components generate heat during operation. Various types of electronic device packages and integrated circuit chips, particularly the central processing unit microprocessor chips, generate a great deal of heat during operation which must be removed to prevent adverse effects on operation of the system into which the device is installed. For example, a PENTIUM microprocessor, containing millions of transistors, is highly susceptible to overheating which could destroy the microprocessor device itself or other components proximal to the microprocessor.
There are a number of prior art methods to cool heat generating components and objects to avoid device overheating. A block heat sink or heat spreader is commonly placed into communication with the heat generating surface of the object to dissipate the heat therefrom. Such a heat sink typically includes a base member with a number of individual cooling members, such as fins, posts or pins, to assist in the dissipation of heat. The geometry of the cooling members is designed to improve the surface area of the heat sink with the ambient air for optimal heat dissipation. The use of such fins, posts of pins in an optimal geometrical configuration greatly enhances heat dissipation compared to devices with no such additional cooling members, such as a flat heat spreader.
It has been discovered that more efficient cooling of electronics can be obtained through the use of passive heat pipes which require no external power source and contain no moving parts. Generally, the heat pipe is in the form a vacuum-tight vessel in a particular geometric shape which is evacuated and partially filled with a working fluid. The heat pipe passively transfers heat from a heat generating component to a heat sink where heat is dissipated. As the heat is conducted into the heat pipe, the fluid is vaporized in an evaporator section creating a pressure gradient in the heat pipe. This forces the vapor to flow along the heat pipe to the condenser section, where the vaporized fluid is condensed and turned back to its fluid state by giving up its latent heat of vaporization. The working fluid is then returned to the evaporator section to repeat the process of removing the heat generated by the heat generating component.
Micro heat pipes are small, wickless heat pipes which have a hydraulic diameter of the same order-of-magnitude as the capillary radius of the working fluid. Liquid transport is accomplished by the formation of a mensiscus of fluid in the corners of the heat pipe due to the surface tension forces of the working fluid.
Current methods of micro heat pipe fabrication typically include forming even channels in an inner circumferential surface of a tube followed by pressing the tube to a flat shape. Another method includes forming even channels in a flat plate followed by folding one part of the plate over the other part of the plate. As illustrated by the above examples, in the formation of the micro heat pipe, it is prone to form protrusions on opposite parts of the flat heat pipe, which reduces heat conduct effect between the heat generating component and the heat pipe. Furthermore, in the use of the heat pipe, when the pressure of the evaporator section of the heat pipe is a little high the two parts of the heat pipe are easy to expand away from each other, which reduces heat dissipation performance of the heat pipe.